JP5131742B2 - Foundation construction method for revetment structures - Google Patents

Description

  The present invention relates to a partition revetment construction method for constructing a part of a sea area inside a cove or a large bay so as to be partitioned into a predetermined area and providing the partitioned section as a waste disposal treatment site. In particular, the present invention relates to a method for constructing a support foundation when a structure is erected on the seabed.

Generally, a part of the sea area that is not easily affected by rough waves in the large bay or the open sea is constructed as a disposal site that is divided by revetment, and separated so that water does not flow between the inside of this disposal site and the open sea. Yes. In order to contain the waste accumulated in the disposal site and the water contaminated by contact with the waste inside the partitioned compartment, a partition revetment is installed to prevent it from flowing into the open sea. Constructed and confined. In such a partition revetment, a layer of asphalt mixture is constructed on the seabed ground in order to maintain good water shielding between the bottom of the revetment structure and the surface of the seabed ground as a support layer. In addition, it is configured to maintain water shielding between the foundation on which the structure is placed and the surface where the bottom surface of the structure is in contact with the surface of the ground. (For example, see Patent Document 1).
JP 2006-204965 A

  In order to support the structure at the bottom of the recess by excavating a groove-like recess in the seabed ground that has been improved to improve water-imperviousness as in the conventional example, asphalt or concrete It is common practice to build layers. However, in order to make the surface of the asphalt or concrete layer flat using the self-leveling property, it is necessary to secure a wide area corresponding to the placement amount.

  In addition, the asphalt mixture used when constructing the water shielding layer is a mixture of straight asphalt mixed with stone powder, fine sand, etc., so that space does not occur even when filling a narrow gap, It is used as a material that can exhibit good fluidity. However, the asphalt mixture prepared with the above good fluidity has a unit price per unit volume of several times or a dozen times as much as the asphalt mixture used for road pavement etc. on land. It is expensive. In addition to the fact that the amount of asphalt used is higher than that for land use, in order to construct the asphalt mixture at sea, many special work vessels are used, and it is necessary to rely on diving workers. The working conditions are also different.

  In addition, various conditions associated with work at sea and in the sea, such as poor work environment, being easily affected by the weather, and often very poor work efficiency. There is also. However, the influence of the economic environment in recent years is heading toward the need to reduce the cost of construction such as the creation of landfills. In response to such demands, even in work such as construction of partition revetments, it is currently required to develop construction methods that reduce construction costs without compromising properties such as strength and water barrier properties. It is.

  The present invention can effectively perform the water shielding treatment at the partition revetment, and even if the construction cost of the water shielding layer is reduced, the performance as a highly reliable water shielding portion is equivalent to that of the conventional partition revetment. The purpose is to provide a method that can be maintained.

The present invention is a construction method of a partition revetment for constructing caisson-like structures in a row on the seabed, partitioning the sea area into a predetermined area, and dumping waste into the partitioned internal compartment About.
In the invention of claim 1, when constructing the partition revetment, firstly, the ground where the structure is to be installed is treated as an impermeable ground, and then the ground improvement is performed as the impermeable ground. Build a ditch in the ground you went,
Next, in order to eliminate surface irregularities at the bottom of the groove, concrete is cast on the bottom surface of the groove to construct a lower packed bed,
A bottom surface of a concave groove between which the block-like members are erected and between which the block-like members are erected is provided by arranging block-like members having a predetermined thickness on the lower filling layer at regular intervals. Asphalt mixture is placed so as to fill, and a process of making a water-impervious layer that works integrally with the lower filling layer is sequentially applied,
Next, the structure that forms the revetment main body is erected in a row in the groove, and then the asphalt mixture is filled so as to fill a gap between the base of the structure and the groove. In addition, a water shielding treatment is performed so that the base of the structure and the water shielding layer of the impermeable ground are integrated.

In the invention of claim 2, on the bottom filling layer constructed as a support layer of the structure on the bottom surface of the concave groove, block-like members provided with a large number of through-holes are arranged at regular intervals, After constructing the support layer of the structure and standing the structure in a row,
A water-impervious structure that integrates the ground and the structure so as not to create a gap between the ground and the structure by performing a treatment to fill the water-impervious material between the base of the structure and the groove. It is constructed as a partition revetment that demonstrates

  As described above, when constructing the foundation for standing and holding the structure, even if unevenness remains on the surface of the support base, the structure constructed on the ground was formed flat. Since it can be erected on the support surface, the construction of the revetment structure can be done easily. And it can construct | assemble so that the bottom face of a structure may contact | connect without a clearance gap with respect to the upper surface which supports the structure of a support base, and can improve the construction efficiency by a diving worker even if it is a work on the seabed. Furthermore, even if the surface of the concrete layer to be placed as a foundation is not flat correctly, no gap is formed between the bottom of the structure by the asphalt layer to be constructed on the foundation and the structure. No loss of water barrier between the bottom of the object.

  Furthermore, the block-like member to be arranged at the structure construction site is one that has a through-hole with an arbitrary cross-sectional shape or one that does not have a hole, supports the structure, and places an asphalt mixture around it. Thus, the water shielding layer can be easily constructed. In addition, since the asphalt mat or the like can be provided in place of the block-like member, it is positioned in the asphalt mixture using a material available on the site, and the support layer of the structure is a water shielding layer. Can be easily constructed.

According to the illustrated example, the configuration of the embodiment of the present invention will be described. In the embodiment described below, a ready-made revetment structure such as a caisson is used to divide a sea area where waste is buried and dumped. This is explained using an example of building a revetment by lining up. In the submarine ground where the partition revetment is constructed, a revetment structure such as a caisson constructed by standing on the ground is constructed according to a predetermined procedure in the same manner as when using a conventional construction method, It can be built by standing up.
In addition, when applying this construction method, it is made to respond | correspond to the said support base and the seabed ground also by performing the process which exhibits the water impermeability similar to a seawall.

  When the partition revetment is used as a section of a waste landfill site, a water shielding treatment is performed so that water shielding can be maintained well at a connection portion of a structure such as a caisson arranged in a row. ing. Further, when configuring the partition revetment, a sheet or mat exhibiting water shielding is laid on the ground where the structure is erected to cover the ground surface and between the bottom surface of the structure. It is processed so that no gap is generated, and the structure is stably supported on the ground. By configuring as described above, even if a large force is locally applied to the revetment from the outside, the caisson constructed in a row is greatly moved or the caisson connecting portion is filled. It will be described below that it is possible to make the structure capable of maintaining the performance as a water-impervious wall for a long period of time without causing significant deformation in the water material.

  The example illustrated in FIG. 1 uses a caisson 2 created on land with a predetermined size, and between each caisson arranged in a line at the construction site, a process of filling a water shielding material is performed. A water shielding layer 3 is provided. And the side of the revetment side of the revetment 1 is provided with a layer of a water-impervious material if necessary, and is constructed as a partition revetment 1 by applying a water-impervious treatment across the revetment main body and its side. Explains. In order to construct the partition revetment 1, the caisson 2 is used in the same manner as in the examples conventionally used as a revetment or a breakwater. The caisson 2 is made of concrete or steel, or is made of a structure having an arbitrary structure such as a hybrid made of steel with a concrete covering on the surface of a steel casing, or a large concrete block-like one. Can be used.

In order to construct the revetment 1 by laying the caissons 2 on the seabed ground, the ground improvement process was performed over a predetermined range of the seabed ground 10 corresponding to the part where the caisson was erected. The water treatment layer 11 is constructed. Then, the ground is excavated from above to form a groove-shaped excavation recess 12, and a foundation structure that supports the structure is constructed at the bottom of the excavation recess 12.
The foundation structure is configured to eliminate unevenness (unevenness) on the bottom surface 13 of the excavated concave groove 12. The lower filling layer 14 is constructed by placing concrete, and the upper surface of the concrete layer is flattened to construct the support layer 20 for erecting the structure.

  It should be noted that the unevenness on the bottom surface of the groove of the excavation recess 12 is required to make the ground surface as flat as possible when a submarine worker performs the work on the seabed. Therefore, it is difficult to expect a large amount of conditions such as flatness due to the problem of workability. Therefore, in order to prevent the unevenness from appearing greatly on the ground surface at the support portion with which the bottom surface of the structure is in contact, and to make it possible to more effectively demonstrate the effect of construction of a water shielding work, As a support layer in which is placed, the lower filling layer 14 may be added and applied.

  The lower filling layer 14 as the support layer is provided on the bottom surface of the groove of the excavation recess 12 that supports the structure to correct unevenness (unevenness) generated during excavation. And the said support layer is located so that a clearance gap may not arise between the bottom face (structure support surface) of the recessed part 12 excavated in the ground, and the bottom face of the said structure. In addition, in the ground where the recess 12 constructed by excavating to the predetermined depth and having the groove shape is positioned, a water shielding material is inserted into the ground to a predetermined depth up to a predetermined range on both sides of the sea land including the recess. The ground improvement part 11 which performed the water shielding process, such as injecting, is provided. Therefore, even if the geology of the ground for constructing the revetment 1 is a water-permeable ground or sandy ground, it is possible to form an impermeable layer by providing the ground improvement portion 11.

  As described above, after the seabed ground at the position where the revetment is constructed is subjected to the treatment of making it impermeable, the support layer 20 that supports the bottom of the caisson is provided on the lower filling layer 14. The bottom surface (footing) 4 of the caisson as a structure is brought into close contact with the upper surface of the support layer 20 so as to be integrated so as not to allow water to pass therethrough. As the support layer 20, an example in which an asphalt mat having a thickness of about 15 cm is laid is illustrated in FIG. 1, and the support layer 20 is pressed by the weight of the structure. To. And by standing the caisson between the mats, the water barrier between the ground and the caisson is also provided between the caisson bottom plate and the lower layer where the asphalt mat layer touches the top and bottom. It is possible to demonstrate well.

  In the example shown in FIG. 2, apart from the example described in FIG. 1, the leveled concrete layer is applied as the lower filling layer 14 on the bottom surface 13 of the excavation recess 12, and further on the filling layer 14. The water shielding layer to be provided is composed of the asphalt layer 21. As described above with reference to FIG. 3, the asphalt layer 21 is formed by laying block-shaped members 22 each having a thickness H, a width W, and a length L according to the length of the caisson at predetermined intervals. Provide.

  Then, the thickness of the block-shaped member 22 is used as a scale member, and asphalt is placed at a height corresponding to the member, and as shown in FIG. It is integrated with the asphalt mixture and constructed as an asphalt layer 21. The block-like member 22 is actually formed with a thickness H of about 15 cm and W = 30 cm, and a length L that can be handled by a diving worker in the sea. Are laid side by side so as to have a predetermined interval.

  Then, as illustrated in FIG. 2, the asphalt mixture is placed on the entire bottom including the block-shaped member 22 on the basis of the thickness (H) of the block-shaped member 22 to include the block-shaped member. The support layer 20 having the asphalt layer as the composite support layer 23 is constructed. When the block-like member 22 is used as a scale for constructing an asphalt layer, there is a defect that a gap occurs between the block-like member 22 and the asphalt to be placed later. There is concern. Therefore, in order to prevent a gap from being generated in the lower part of the block-like member 22 or in the periphery thereof, as shown in FIG. It is considered that asphalt should be filled without gaps.

  Providing the block-shaped member 22 with a vertically penetrating hole means that, when the block-shaped member is manufactured, a rod having a predetermined thickness is pushed into the asphalt mixture and the rod is formed after molding. It can be made by applying a process such as pulling out. In addition, after the block-shaped member 22 is formed in a predetermined shape, it may be manufactured using a technique such as inserting a pipe or the like to make a hole. As shown in FIG. 4 (a), the holes formed in the block-shaped member 22 can be provided with round holes 22a having an arbitrary diameter at arbitrary intervals. The holes 22a are formed asphalt having fluidity. Of course, it should be large enough to pass. Further, the through hole may be a round hole as shown in FIG. 5B, but may alternatively be a hole 22b having a square cross section as shown in FIG. In addition, it is needless to say that the hole may have an elliptical cross section or a rectangular square cross section.

  The block-shaped member 22 shown in the figure is not particularly limited to one obtained by molding an asphalt mixture into a block shape, and may be made using rubber or any plastic material. In the example in which the block-shaped member is made of a plastic material, if it has elasticity similar to that of rubber or the like, it is deformed by being pressed by the weight of the structure built on it as well as asphalt placed around it. Therefore, it can maintain so that a clearance gap may not arise between the upper surface of the support layer 14, and the bottom face of a structure.

  Further, the hole provided in the block-like member is formed so as to penetrate in the vertical direction of the block, and the hole may be provided so as to penetrate through the side surfaces on both sides of the block. Further, each of the through holes is not only provided horizontally and vertically, but also provided with a hole through which the block is inclined, so that the asphalt mixture placed in the support layer 20 is provided in the block-like member. If there is a gap on the side of the block-like member through the hole, the gap is assisted. In addition, by forming the holes provided in this block-shaped member to an arbitrary size, among the solids contained in the asphalt mixture, relatively large lumps, liquid, air bubbles, etc. , It can be moved to a position where it does not get in the way, or it can be discharged to the outside. Therefore, by providing a hole in the block-shaped member, in the water shielding layer filled with the asphalt mixture, foreign substances that adversely affect the properties of the water shielding layer due to the asphalt mixture are mixed in unfavorable positions. No longer left behind.

  As described above, by providing a large number of holes penetrating the block-shaped member in an arbitrary direction, the lower filling layer 14 is formed on the lower surface of the concave portion where the structure is installed, as illustrated in FIG. Even when a crack 14A is generated and a gap is formed in the provided concrete layer, it can be easily handled. That is, the asphalt mixture of the support layer 20 flows toward the gap of the crack 14A toward the gap due to the crack 14A generated in the lower filling layer 14, and the gap is automatically closed, so that the gap remains as it is. In this way, it can be protected so as not to impair the properties of the water shielding layer.

  The example shown in FIG. 6 differs from the example described in FIGS. 2 and 5 in the case where the support layer 23 is configured by laying an asphalt mat between the lower filling layer 14 and the bottom surface of the structure 2. It is what is being explained. In this example, the structure and structure of the asphalt mat is not particularly limited, and can be provided with a stack of arbitrary thickness. The width and length of the asphalt mat also matches the situation at the construction site. Can be selected.

Then, the mat having an arbitrary thickness is applied so as to cover the entire surface of the lower filling layer 14 or in an area corresponding to the bottom surface of the structure 2, and between the side surface and the mat layers 23, 23, Place the asphalt mixture. By being configured as described above, the asphalt mixture to be placed is filled and integrated between the upper and lower mats of the mat layer and the middle portion of the mat layer, and the lower surface of the bottom member 4 of the structure 2 is Then, it comes to stand on the lower filling layer 14 without a gap.
In the example illustrated in FIG. 6, the asphalt mat member 23 is arranged so as to be continuous in the length direction in which the caisson as the structure are arranged. On the other hand, it can be made integral by filling the asphalt mixture and filling the gap.

  Further, when the layer 20 in which the asphalt mixture is cast including the block-shaped member 22 is constructed, a gap 21a is generated on the lower surface or side portion of the block-shaped member 22 without being filled with the asphalt mixture. It is thought that a situation may occur. However, even in a state where such a space containing air remains, in the portion where the gap is located, the surrounding asphalt mixture passes through the holes 22a, 22c, etc. provided in the block-like member, It is moved toward the gap 21a. At the same time, the air in the gap is also discharged through the hole provided in the block-like member, and the action of automatically replacing the gap with asphalt is performed, so that the gap is not left as it is.

Furthermore, by providing a hole with a predetermined diameter vertically through the block, when building an asphalt mixture layer on the lower packed bed 14, it is also provided on the lower and side surfaces of the block. It becomes possible to perform a process of filling asphalt without gaps.
Further, in addition to constructing a layer of the asphalt mixture including the block-shaped member inside and integrating the block-shaped member, in addition to the support layer 20, for any surface such as a side surface of the groove, By laying a thin asphalt sheet, it is possible to provide means for protecting the side surface of the recess. When a sheet-like material is laid in addition to the support layer 20 provided in the excavation recess 12, any surface of the groove is protected by using a sheet of plastic or rubber having an arbitrary thickness. Can be laid.

  In addition, as described above, for the partition revetment provided by standing a structure, a groove is excavated in the seabed ground that constructs it, and the unevenness remaining at the bottom of the groove is covered. By constructing a concrete layer with an arbitrary thickness and leveling the surface of the concrete layer, the bottom surface of the structure standing on the concrete layer can be stably positioned. Further, by constructing the asphalt mixture layer with a predetermined thickness on the concrete layer, the bottom surface of the structure standing as a partition revetment can be positioned stably. Further, when the asphalt mixture layer is constructed, the thickness of the asphalt mixture layer is regulated by using block-like members arranged at regular intervals, whereby the asphalt mixture layer has a constant thickness. Can be constructed, and the work can be easily performed.

It is sectional drawing explaining the structure of the partition revetment which divides a waste disposal site. It is explanatory drawing which shows the relationship between the lower part of a revetment and the ground. It is explanatory drawing of a structure of a block-shaped member. It is explanatory drawing of the through-hole provided in a block-shaped member, The figure (a) is a cross section, (b) and (c) are top views which show the shape of a hole. It is explanatory drawing of the effect | action of repair of the impermeable layer in the lower part of a structure. It is explanatory drawing of the support layer different from FIG.

Explanation of symbols

1 revetment, 2 caisson, 10 submarine ground, 11 ground improvement treatment layer,
12 excavation recess, 13 bottom surface, 14 lower packed bed,
15 side impermeable layer packing layer, 20 support layer, 21 asphalt layer,
22 block-like members, 23 mat layers.

Claims (2)

It is a construction method of a partition revetment for constructing caisson-like structures in a row on the seabed ground and partitioning the sea area into a predetermined area, and dumping waste into the partitioned internal compartment,
When constructing the partition revetment, firstly, the ground where the structure is to be installed is treated as an impermeable improved ground, and then a groove is formed in the ground that has been improved into the impermeable ground. Build and
Next, in order to eliminate surface irregularities at the bottom of the groove, concrete is cast on the bottom surface of the groove to construct a lower packed bed,
A bottom surface of a concave groove between which the block-like members are erected and between which the block-like members are erected is provided by arranging block-like members having a predetermined thickness on the lower filling layer at regular intervals. Asphalt mixture is placed so as to fill, and a process of making a water-impervious layer that works integrally with the lower filling layer is sequentially applied,
Next, the structure that forms the revetment main body is erected in a row in the groove, and then the asphalt mixture is filled so as to fill a gap between the base of the structure and the groove. In addition, a foundation construction method for a revetment structure of a partition revetment , wherein a water impermeability treatment is performed so that a base portion of the structure and a water impervious layer of an impermeable ground are integrated . On the bottom filling layer to be constructed as a support layer of the structure on the bottom surface of the concave groove, block-like members provided with a large number of through holes are arranged at regular intervals, and the support layer of the structure is provided. After building the above structure in a row,
A water-impervious structure that integrates the ground and the structure so as not to create a gap between the ground and the structure by performing a treatment to fill the water-impervious material between the base of the structure and the groove. The foundation construction method of the revetment structure of a partition revetment according to claim 1 , characterized in that it is constructed as a partition revetment that exerts its effect .

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